Abstract

Chemical analysis showed that the debris collected from the yoke tube consisted of oxides of the base material elements. In addition, chlorine as high as 0.6 wt% was found present. The morphology of the debris was found to be typical of scales that form on the surface of the steel components during heat treatment. It appears that these scales were present on the inner surface of the yoke tube and would have peeled off due to vibration during service. However, the presence of chlorine cannot be ignored since it can give rise to different forms of corrosion in a long run. It is, therefore, necessary to identify the source of chlorine and accordingly, corrective measures need to be incorporated.